Abstract

The interest in the analysis of the multimode instability of ring fibre lasers has increased in the recent years because of the identification of such instability in Er³⁺-doped fibre lasers as the classical Risken-Nummedal instability [1,2]. Two factors not considered up to now play a major role on the lasing to instability thresholds ratio, r: (i) the transverse profile of pump and lasing fields due to their guided nature, and the extension of the doped region within the fibre core; and (ii) the inhomogeneous broadening of the Er³⁺ gain induced by the fibre host.

© 2000 IEEE